Truth
by fireworksinthenight
Summary: Donatello experiments with a truth serum. Mayhem ensues.
1. Where Someone Shouldn't Have Interfered

_Author's Note: I do not own the turtles. Set in the 2012 universe, an undefined amount of time before the beginning of the first season._

 _Once I had this idea, it wouldn't leave me in peace. So I had to write it down._

 **Where Someone Shouldn't Have Interfered**

Donatello was carefully pouring some blue liquid into a test tube. His focus was so intense that he was unconsciously sticking his tongue out. He was looking forward to discovering what amazing properties his new mixture had. No one else had ever mixed the same components in the same way, he was certain of it. It was partly because scientists rarely used sewer ooze in their experiments, and partly because none of the chemistry books and advanced scientific articles that he had illegally downloaded on his computer reported it or anything like it.

Donatello smiled fondly. He had taken great pleasure in reading those books and articles, sometimes in the middle of the night, huddled under his comfy quilt. However, he would have to find a way to make said quilt opaque – his father hadn't been too happy about his pastime when he had caught him because of the suspicious light it emitted. As if three in the morning wasn't an appropriate time for expanding one's knowledge. Donatello shook his head at the absurdity of his father's view on the topic.

There – this delicate task was almost performed. What was he going to begin with? Maybe spread it on one of his cell cultures, see if it was biologically dangerous. Or maybe…

"Boo!"

Donatello jumped, spilling some of his precious mixture on his lab's floor.

"Mikey!" He roared. "How many times have I told you not to disturb me when I'm in the middle of an experiment?"

The incriminated brother grinned despite Donatello's furious glare.

"I don't know, Donnie. How many?"

"Seventy-three times this week," Donatello went on. "This could be dangerous. You don't even know what's in this test tube! What if it is poisonous to orange-clad turtles?"

Donatello suddenly leaned to shake his tube in front of his brother, careful not to spill any more of the liquid.

"Maybe a drop of it would be enough to send you into a catatonic state!" He said menacingly.

Michelangelo's eyes widened and he retreated with a sheepish grin.

"Noooo, I don't think so, brother mine. See?"

The orange-clad turtle happily waved his left hand.

"Some of it dropped on my skin and I'm still feeling awesome!"

Donatello's mouth dropped.

"What?"

He hurriedly put his test tube away and caught his brother's hand, inspecting it closely. There it was, a drop of blue liquid. Donatello wiped it with a clean cloth.

"Are you sure that you're feeling okay?"

Michelangelo's eyes gleamed.

"Now that you're talking about it…"

"What is it, Mikey?" Donatello anxiously asked the orange-clad turtle. "Are you feeling dizzy? Does it itch? Do you have a headache?"

"Well, I…"

"Tell me!" Donatello was begging now. Michelangelo shot him a trademark smile.

"I think I'm hungry!"

Donatello looked at his brother, speechless. Then he calmly put the cloth away and abruptly pulled Michelangelo's hand so that the orange-clad turtle crashed on the floor. Using both his legs and arms, Donatello pinned his brother to the ground.

"It's _not_ funny," he whispered in Michelangelo's ear. It was a very threatening whisper.

"Okay, okay!" Michelangelo protested. "I apologize, you're right, I shouldn't have. You know better, O Mighty Genius. Please have mercy!"

Donatello released him. Michelangelo dusted his shell, sighing a little exaggeratedly.

"Ouch. _Now_ I'm hurting."

Donatello rolled his eyes.

"Seriously, Mikey. If you feel strange, tell me at once, okay?"

Michelangelo nodded.

"Don't worry, bro."

"Good. And now… GET OUT OF MY LAB!"

Michelangelo hurriedly retreated, his hands pressed on his ears in a desperate attempt to protect his sense of hearing.

%%%%%

Michelangelo glanced at the living room. Annoying Donatello had been fun – it always was. Now the orange-clad turtle was looking for his next victim.

And here, on the couch, sat the perfect candidate. A red-clad turtle who was half-watching a TV show and half-feeding his pet turtle Spike.

Michelangelo crept towards his unsuspecting brother. Maybe he could shout "Boo!" in his ears too? Raphael wouldn't immediately chase him, he would delicately place Spike on the couch before, giving Michelangelo a few precious seconds to run for his life.

The orange-clad turtle crept closer, and closer, and…

"Don't even think about it, Mikey."

Michelangelo pouted and jumped the back of the couch to land next to his brother.

"Not fair! How did you know I was there?"

"I'm a ninja," Raphael replied smugly. "Plus Donnie's shout betrayed that you are in prank mode."

The red-clad turtle grinned at Michelangelo, showing his teeth at the same time.

"I'm sure you weren't seriously considering pranking me?"

Michelangelo laughed nervously, ready to deny it.

"Of course I wanted to, bro," he heard himself say instead.

Raphael looked at him in disbelief.

"Can you repeat? I don't think I heard you correctly."

"I said I wanted to prank you, Raph. But it doesn't matter if it didn't work right now, I will just wait for another occasion. Maybe trap your room's door again, or…"

"Whaaaaaaat?"

Horrified, Michelangelo put his hands against his mouth to prevent himself from talking. Unfortunately for him, his muffled words were still understandable.

"…you looked so beautiful last time I mixed pink paint with your soap, I was considering doing it again…"

"You're so dead, Mikey!" Raphael roared.

Yelping, Michelangelo seized a nearby cushion and bit it. At least that way, his treacherous mouth would stop digging his grave.

However, he had lost precious seconds in doing so and Raphael had already put Spike away. Now his red-clad brother was launching himself at him, hands outstretched. Michelangelo tried to escape Raphael's wrath, to no avail.

"Excellent idea, this cushion," Raphael growled. "It will muffle your cries of pain."

Michelangelo made puppy-dog eyes, but Raphael wasn't looking at him.

"See, Spike?" The red-clad turtle was saying. "This is how you punish brothers who think they can prank you without suffering the consequences and… ouch! Mikey! Come back here!"

%%%%%

Donatello was taking notes in his lab notebook when he heard someone carefully open the door. He turned to see a rather beaten-looking Michelangelo, biting a red cushion with strength, tiptoe into the lab and close the door carefully.

Michelangelo released the cushion and looked at his brother with pleading eyes.

"If Raph asks, I'm not here," he said breathlessly.

Donatello tilted his head.

"And why should I grant you that?"

Michelangelo came closer and put his hands on Donatello's shoulders, shaking his brother slightly.

"Because it's your fault, bro!"

Donatello opened his mouth to reply, but he was interrupted by a threatening growl outside the door.

" _Mikeyyyyyyyyyy_ …"

Michelangelo picked up his cushion, bit it again and threw himself under Donatello's desk.


	2. Where Someone Is Proud Of Himself

_AN: Mikell (or Mary?): Thanks for reviewing! Poor Mikey indeed. And it isn't over…_

 _Techno Dawn: Thank you! I'm glad you enjoyed the chapter!_

 _Starfire201: Oh, yes. You are so right. Thanks for leaving a review!_

 **Where Someone Is Proud Of Himself**

Donatello sighed and pushed a weird-looking machine in front of the desk to hide his not-so-discreet brother. Then he quickly took googles, a white lab coat and a test tube at random. He was curious to hear Michelangelo's explanation, and it was obvious that the prankster wouldn't leave the relative safety of Donatello's desk while Raphael was chasing him.

However, the purple-clad turtle was fairly confident that this matter would be settled soon. Unlike Michelangelo, Raphael was rightfully afraid of Donatello's chemical experiments.

When Raphael knocked on the door, Donatello was ready and offered the image of a perfect mad scientist.

"Come in," Donatello answered in his best mad scientist voice, the one which said _I'm only half-paying attention to you because what I'm handling right now has a very promising destructive potential._

Raphael put a fuming head out of the door.

"Have you seen Mikey?" He asked in a half-furious and half-careful voice.

"No," Donatello pretended. "Not since I threw him out."

Raphael looked at him suspiciously.

"Are you sure?"

"Of course I am. Can't you see I'm busy with this test tube?"

"It's empty," Raphael remarked.

It was true. Donatello cursed inwardly. In his haste, he hadn't picked the right one. But he wasn't going to acknowledge that.

"The liquid it contains has the same refractive index than the glass of the test tube," he said instead in a supremely disdainful tone. "That's why you can't see it. If you want, I can give you a short course in optics later. I think your physics knowledge leaves a lot to be desired and…"

"No, thank you very much," Raphael quickly interrupted him. He knew a genuine threat when he saw one. "In another lifetime, maybe. And if you see Mikey, tell him he will get what's coming for him!"

Without waiting for Donatello's reply, Raphael disappeared.

Satisfied, Donatello took off his scientist costume and bent over his desk.

"The course is clear," he said dryly. "Now what is it about?"

%%%%%

"And then, my mouth began to say things it shouldn't have, as if my brain wasn't commanding it anymore!"

Michelangelo was pacing the lab, juggling with his cushion and keeping an ear out for Raphael's return.

"Isn't it always the case?" Donatello remarked, earning a hurt glance from his brother.

"Noooo, bro! It was much worse! Raph asked if I wanted to prank him, and not only did I say yes, but I also began to detail my awesome ideas…"

"That's why Raph was mad at you," Donatello nodded gravely. "I can't blame the guy, then."

"It was so wrong! It totally ruined the surprise! How can I efficiently prank if I can't help telling my prey about it?"

"Your prey?" Donatello asked wryly. "You're thinking of _Raphael_ as your prey?"

"Not only Raph, but Leo and you are, too! Defenseless against my wit and cleverness!" Michelangelo exclaimed, before clasping his hands over his mouth again. "See? It's happening again!"

Donatello was perplexed and a little offended.

"I'm anything but defenseless, Mikey," he protested. "I always get back at you!"

"Not always, bro!" Mikey replied. "Remember last time you searched for that little screw you needed to fix your computer? You never knew _I_ had displaced it!"

"Whaaaat?" Donatello looked at his desperate brother furiously. "It took me hours to find it! I thought it had slid on the floor!"

Then his mind caught on and his spirits lifted.

"You are compelled to tell the truth," Donatello said excitedly. "Since my serum dropped on you! A truth serum! I made a truth serum!"

The genius turtle couldn't believe it. This was epic!

"This is epic!" He said aloud.

Michelangelo shook his head.

"You wouldn't be saying that if you were the one Raph wants to reduce to a pulp," he said miserably.

Donatello wasn't listening to him.

"I wonder how long it lasts," he muttered. "Or how efficient it is. No offense, Mikey, but you're already a chatterbox. What would the effect be on someone more reserved?"

Michelangelo's eyes lit.

"You want to test it on someone else? Now you're talking my language!"

Donatello grinned evilly.

"Yes, I certainly will. But first…"

The purple-clad turtle sat on his desk and took a sheet of paper and a pen.

"While you have to stay in my lab for safekeeping, let's have a talk. Mikey, can you give me a list of every prank you pulled on me in, say, the last month?"

Michelangelo looked at him with horror.

%%%%%

Half an hour later, Donatello knew that the serum effects were short-lived. He also knew that his brother was far better at avoiding trouble than he would have granted him.

Michelangelo was tied up on a chair in front of him – a necessary evil to keep him from biting his cushion to prevent himself from talking – and looked rather defeated.

Donatello gathered his notes and watched his brother with intensity. It was time to make a deal.

"Now, Mikey," he began. "Considering what I've here – not only what you did to me, but also what you did to Raph and Leo, along with the true story of what happened to Sensei's favorite teacup…"

Michelangelo looked at him with despair.

"Please, Donnie, no! My beloved brother, the best and kindest of all, don't…"

Donatello bit back a smile. He was so enjoying this.

"I think we can rightfully assume that you would want this information kept between the two of us…"

Michelangelo nodded vigorously.

"… of course, there would be a small price to pay…"

Michelangelo moaned. He was cornered and he knew it. How he regretted to have disturbed Donatello earlier! Now he had given the purple-clad turtle the best leverage any of his brothers could have hoped for.

"…let's say, you don't prank me for an entire week…"

Michelangelo sighed. It could have been worse.

"Okay."

"…And I get full access to your video games and comic books…"

The orange-clad turtle whined. It wasn't over?

"O…okay."

"…and you watch the scientific channels I choose for you for one month, and you learn how to repair the TV remote yourself."

"Donnie! Do you want my death?"

The purple-clad turtle grinned at him and fanned himself with the notes revealing Michelangelo's deeds.

"If you can't stand it…"

Michelangelo let out a desperate sigh.

"Fine! Fine, it's a deal. Dude, you drive a hard bargain."

Donatello laughed, pleased with himself.

"Next time, you will think twice before wreaking havoc on my projects."

Michelangelo shrugged. He was happy that the truth serum wasn't effective anymore, or he would have told Donatello that he was already bursting with ideas to get back at him. Of course, he would have to be twice as careful now that the purple-clad turtle knew what he could do.

Donatello untied him.

"Don't be sad, Mikey," he soothed the defeated turtle. "Scientific channels are fun, you will see. And don't you want to witness how Raph will react to the serum?"

At that, Michelangelo perked up.

"Bro, I love it when you use your evil genius at someone else's expense. What can I do to help you?"


	3. Where Someone Doesn't Stay Tough

_AN: Starfire201: It is, isn't it? And I really don't know why you would think that :D_

 _BlingThing: Thanks for reviewing! The next one will be Raph, and after him, who knows?_

 _Techno Dawn: Thank you! Let's see what happens next…_

 _Hawkfeather: Yes, a new story! :D It's not in the same universe as Just Fine. Leo is around, don't worry! And Donnie is a scientist, maybe a little too curious for his own good. Thanks for reviewing!_

 **Where Someone Doesn't Stay Tough**

Michelangelo hated the first part of Donatello's self-proclaimed Clever Plan for Testing The Truth Serum On Raphael, mainly because it involved allowing his purple-clad brother to jab him with a needle.

The orange-clad turtle whined.

"Is there really no other solution?"

Donatello was patiently waiting in front of him, one hand calmly set on Michelangelo's shoulder and the other hand behind his back, concealing the sharp needle so that Michelangelo didn't totally freak out.

"No, I'm sorry. I need a sample of your blood. I want to do a few tests to make sure that the serum isn't dangerous. Unlike you, I'm a cautious and responsible turtle."

"Unlike me?" Michelangelo snickered. "I wasn't the one who almost blew up the lair last month."

Donatello blushed.

"A slight mistake in my gas pressure calculations. It happens to the best of us. Now are you ready?"

"Nooo, not yet. Why are you so eager to prank Raph anyways? I mean, it's more like my department."

"First, he's never going to know it. Second, I'm really short of test subjects here in the sewers. I can't be picky."

"So it has nothing to do with the fact that he totally humiliated you in our training session this morning?"

"Absolutely nothing. Your arm now, Mikey, please."

"Why does it have to be a needle? I hate needles."

"Few people like them, Mikey. Think at the next part of our plan. Don't you like your role in it? Now, on the count of three… One… Two…"

"Ouch! You cheater, you said three!"

"Sorry. There, it's done."

Michelangelo sighed in relief and rubbed his sore arm. He really hoped that the serum was harmless, and not only out of concern for his own health. He loved the second part of Donatello's Clever Plan for Testing The Truth Serum On Raphael.

%%%%%

"There," Donatello said. "I think it has the right concentration of serum, and it's transparent."

The purple-clad turtle handed Michelangelo a small bottle filled with a liquid which could have been water, except it also contained a drop of the truth serum which had been deemed harmless. Michelangelo took it and poured it inside a yellow balloon which he deftly closed.

"Aim at Raph's arms or legs, not his shell," Donatello recommended.

Michelangelo pretended to be deeply hurt.

"Dude, you're breaking my heart. I am the king of water balloons. I never miss! Raph won't know what hit him until it's too late."

Donatello nodded.

"Alright. Leo and Sensei should return home soon and it's my turn to make dinner. It's time for you to find another shelter."

Michelangelo looked at his brother with pleading eyes.

"Can I stay in your lab? I want to wait until the last minute. I have a feeling I'll need Sensei's protection after Raph will have met with this yellow beauty here."

Donatello shook his head, deadly serious.

"No way, Mikey. You alone in my lab? Not in a million years."

Michelangelo sighed. Then he weighed up his balloon and looked at his brother with a wicked grin.

"You know, Donnie, I could just throw it at you. See what _you_ have to hide."

Donatello smiled back. He felt entirely confident.

"So I would be compelled to reveal your darkest secrets to our whole family? Your move, Mikey."

Michelangelo bit his lip, disappointed.

"On second thought, I think I will go along with your plan."

"That's what I thought."

%%%%%

After having thoroughly searched the entire lair without being able to find Michelangelo, Raphael had calmed down. Now he was more perplexed than angry. Michelangelo didn't usually reveal his future pranks so easily. Or maybe it was a new strategy to get on Raphael's nerves? The red-clad turtle shrugged. _It's Mikey_ , he thought. _How knows how the guy thinks?_ Raphael had no doubt that his brother would reappear soon and he decided to postpone his revenge. Now was the time for a nice relaxing activity.

A while later, he was cursing and shaking a Space Heroes pinball machine in his vain attempts to beat Leonardo's high score, his ninja eyes focused on the bouncing little ball. That's why he didn't immediately react when something wet hit his arm. Then he looked in disbelief at the remnants of yellow rubber on his skin, and he turned furiously to meet Michelangelo's gaze. The orange-clad turtle was grinning at him from the opposite side of the living room.

"Hey, Raph," Michelangelo shouted. "I'm disappointed in you, you know. I thought you would keep searching for me a while longer. Your thick body could use the exercise, after all. So I thought I would give you a little something to help you with your motivation…"

Raphael's mouth dropped. Then his temper flared again and he launched himself at his orange-clad brother, chasing him through the living room. It took a few minutes, but he finally had the offensive brother pinned to the floor. Unfortunately for Raphael, Michelangelo had timed his intervention well. The red-clad turtle hadn't even begun to punch him when the commanding voice of Master Splinter himself resonated.

"Raphael! Release your brother this instant!"

Raphael immediately obeyed.

"But Sensei," he nonetheless protested, "Mikey started it!"

Master Splinter shook his head, nimbly jumping the turnstiles despite the heavy backpack he carried. Leonardo was following him with a smaller backpack.

"Then be the clever one and finish it. In a non-violent way."

Raphael muttered something.

"What was it, Raphael?" Splinter asked, rising an eyebrow.

"I was saying, non-violence is boring," Raphael answered louder, before looking horrified. In front of him, Leonardo's eyes widened.

Master Splinter looked at him with surprise. A second later, he had dropped off his backpack and was sitting on Raphael's plastron, his red-clad son sprawled on the floor.

"Ouch," Michelangelo said with compassion. Not that he regretted his role in putting Raphael in this uncomfortable situation, of course.

"Boredom isn't always a bad thing, don't you think?"

Master Splinter winked at Raphael.

"I guess not, Sensei," the red-clad turtle answered in a choked voice.

Donatello chose this moment to exit the kitchen. He had witnessed the entire scene and was stifling a laugh. Apparently, the serum also worked on Raphael.

"Dinner is ready! I heated up the algae and worms pudding Mikey did yesterday."

Leonardo and Raphael sighed, while Michelangelo nodded approvingly.

"A true delicacy," the orange-clad turtle said, one green finger up.

%%%%%

"So, have you been lucky in scavenging today?" Michelangelo asked, his mouth full with the green mixture he called a pudding.

"Mind your manners, my son," Splinter reprimanded him in a resigned voice. "And yes, we were. We found most of the spare parts that Donatello asked for, along with blankets almost as good as new."

Leonardo smiled innocently at his orange-clad brother.

"And I may have found a few torn comic books in the process. The things people throw away…"

Michelangelo's eyes lit and he put his spoon down, leaning towards Leonardo in an overexcited way.

"Comic books? Why didn't you tell me right away? Which ones, which ones?"

Eyes gleaming, Leonardo took another spoonful of pudding and chewed it at length before answering.

"I don't remember exactly. I guess you'll have to wait until dinner is over…"

"Leoooo," Michelangelo moaned. "Don't do that to me, bro!"

Leonardo only smiled and began to take another spoonful. Michelangelo looked at his father, hoping that he would let him leave the table to check the promised comic books right now. But Master Splinter shook his head, secretly amused by his sons' antics. Michelangelo moaned and turned his attention back to Leonardo, who was keeping a straight face. He should have kept his truth-serum-loaded water balloon for this annoying turtle. Maybe Donatello would give him another one later?

While Leonardo was teasing Michelangelo, pretending not to remember how many superheroes had been on the covers and what their costumes were, Donatello was discreetly watching Raphael. He had calculated the serum dose so that it would only work during dinner time. However, Raphael hadn't been making conversation so far and Donatello didn't dare to ask him questions. He didn't want the red-clad turtle to become suspicious.

Luckily for him, an occasion soon presented itself. Master Splinter had decided to ignore Leonardo and Michelangelo, and especially the way some of Michelangelo's pudding had mysteriously landed on Leonardo's face, and to focus on his two other and more reasonable sons.

"My sons, how did your afternoon go?"

 _Yes_ , Donatello thought. He quickly answered.

"It was fine, Sensei. I'm making progress with my experiments."

"Very good, my son. And you, Raphael? What have you been doing?"

Raphael looked at his father, wanting to answer that he had spent a nice afternoon working out and then watching TV.

"I entertained Spike by chasing Mikey down," he answered instead.

Master Splinter's eyes widened, not quite sure how to react.

"Are you sure it's an appropriate way to entertain a little turtle such as Spike?"

"Yes, he loves it! And I do too! It's so fun to chase Mikey around and then punch him…"

At that stage, everyone was looking at Raphael, who seemed rather confused. Leonardo absent-mindedly wiped his face, wondering what on earth was going on with his red-clad brother.

Master Splinter frowned.

"Raphael, we have already talked about that. You are not supposed to use your superior strength against your brother in such a way. What if you hurt him?"

"Oh, I won't truly hurt him! I just pretend I want to. He's my beloved brother, after all. I will let him prank me until the world ends."

Raphael blushed at the astounded looks of his family. _What's happening to me?_ He thought. _I never meant to say that._

"Ohhh, Raph, it's so sweet!" Michelangelo said, delighted.

"You're all so amazing, I love you so much," Raphael went on, apparently unable to stop. "You're my entire universe. I would do anything for you, I would…"

But they never knew what Raphael would do, because the effect of the truth serum had worn off.

Raphael sat, his mouth still open, his cheeks a brighter red than his bandana, while his brothers and his father looked at him. Donatello tried to look only astounded and not as amused as he felt. He discreetly stopped the tiny recorder he had just used. Michelangelo didn't bother to hide his own amusement, while Leonardo looked rather concerned. Master Splinter had managed to keep a straight face, knowing that any other reaction would deeply injure his son's pride.

"My son, I'm glad that you allowed yourself to be so open to us," Raphael's father said carefully. "I am proud of you."

"I… I'm not feeling so well," Raphael said in a choked voice. "Can I go to bed now?"

"Of course, Raphael," Master Splinter nodded. "Good night."

"I'll finish your plate, don't worry," Michelangelo added, immediately doing as he had said. "And Leo, I know that you remember the comic books you found. Don't you always say that we have to be truthful?"

Donatello said nothing. While Raphael left the kitchen like a zombie, he secretly relished the success of his experiment. This truth serum was awesome! He tried to convince himself that it was enough, that it would become suspicious if someone else succumbed to a fit of sincerity, but deep down, he knew that he wouldn't be able to refrain from testing it on Leonardo too. Maybe his blue-clad brother would confess his eternal love for Captain Ryan? Donatello met Michelangelo's gaze, and saw his anticipation. Yes. He definitely couldn't stop now.


	4. Where Two Turtles Are In Trouble

_AN: BlingThing: And there comes Leo's turn! I hope you enjoy._

 _Nightshadegirl: I'm glad you're enjoying this story! And I'm sure Donnie will choose the shows carefully, he doesn't want to traumatize his brother. Thanks for reviewing!_

 _Techno Dawn: Absolutely. But it still felt good to write him say it aloud…_

 _Hawkfeather: Thank you so much for your kind words! I must say I enjoyed that part… Poor Raph, though! I see you're concerned about Leo's well-being. Well, he doesn't hate himself and he's not the leader yet, so he isn't burdened with this responsibility. (That's basically why I chose to place the story before Splinter makes him leader.) So he should be fine, right?_

 **Where Two Turtles Are In Trouble**

Donatello managed to wait an entire week before testing the truth serum on Leonardo. It had been necessary to let things settle down a little. Raphael's reaction to the serum, although really funny from Donatello's point of view, had awoken his family's suspicions.

Leonardo had been especially worried about Raphael's well-being. He had come to Donatello and asked him if such a reaction could be the symptom of an illness. Donatello had clouded the issue while still reassuring his anxious brother, pretending that Raphael's sudden and brief burst of sentimentality could be due to a temporary tiredness and that he would be fine after a good night's sleep. Leonardo had seemed dubious, but he hadn't pressed the issue, to Donatello's utter relief.

Master Splinter had said nothing, but Donatello knew that he was concerned too. When Raphael had mercilessly beaten Michelangelo during their next sparring session and boasted about his victory for hours, the ninja master hadn't say a single word to reprimand him.

Raphael had his suspicions too. He had asked Donatello if he had put something in his food while preparing dinner. Donatello had played the offended turtle with shameless conviction, helped in that by the fact he was being sincere. Besides, Michelangelo had finished Raphael's plate, so the food was out of the picture. This argument had convinced Raphael, who had shook his head and left grumbling. May their orange-clad brother be blessed for his endless appetite.

Speaking of Michelangelo, the orange-clad turtle was becoming restless. He was harassing Donatello with his pleas for more Truth Water Balloons. It kind of compensated the fact that he kept his promise and didn't prank the genius. Donatello wondered if it was it some sort of revenge. At least the purple-clad turtle had the pleasure to watch educational scientific channels with his brother. Michelangelo's pitiful expression when the genius turtle had switched on the TV with a wide grin and motioned for the orange-clad turtle to take a seat and watch a three hours long report on the building of a new particle accelerator had been priceless. Okay, maybe Donatello had exaggerated a little on this one. He didn't want to put Michelangelo off science – not that the shorter turtle had been into it at some point, but still…

But now, Donatello believed that the incident with Raphael was, if not forgotten, at least behind them. It was time to move on. This time, the purple-clad turtle had planned to use his serum during their training session. It had been Michelangelo's idea.

"That's the least probable place where Leo would talk nonsense," Michelangelo had said excitedly. "It's going to be fun! And maybe Raph will be too distracted to seriously spar with us."

That last part had convinced Donatello. He could do with a lighter training session today. After all, he had spent a considerable amount of time reading under his new opaque quilt last night and he was tired.

That's why Donatello had discreetly dropped off some of his serum on the hilts of Leonardo's katana while Michelangelo distracted their blue-clad brother, just before their training session. If everything went well, Leonardo wouldn't touch them until he had to unsheathe his katana for weapons' practice.

And everything went well up to this part. While Donatello took his bo staff to go through kata who required their weapons, his eyes watched his blue-clad brother anxiously. Would Leonardo notice that his hilts were slightly damp?

But the four turtles were already far in their training session, and they were sweating. To Donatello's relief, Leonardo didn't appear to feel the difference.

During the whole time Master Splinter ordered them to go through kata, Donatello's heart was beating faster with anticipation. It made him make a few unusual mistakes and he glimpsed an amused look on Leonardo's face when Master Splinter had to correct him. _If only you knew, Leo_ , Donatello thought excitedly. _I don't think I will be the main attraction today._

At the same time, the purple-clad turtle couldn't help feeling a tingle of guilt. If Michelangelo had brought his fate upon himself and if Raphael had quite deserved his own due to his smug behavior in the dojo, Leonardo hadn't really done anything to cross his genius brother. _I'm just collecting more data for my research. Two people aren't a wide enough statistical sample,_ Donatello thought with bad faith.

After the kata, Master Splinter motioned for his sons to kneel in front of him.

"My sons, we will continue our training session with one-to-one sparring. Donatello will face Leonardo, and Raphael will face Michelangelo. Then the winners will face each other."

Raphael smiled smugly.

"You can name them, Sensei. We all know who it will be."

Splinter frowned at his arrogant son.

"The outcome of a fight is never certain, my son. Overconfidence can be deadly."

The ninja master looked at his four sons.

"Do you understand?"

"Hai, Sensei," Raphael, Donatello and Michelangelo answered respectfully.

But Leonardo didn't. Splinter turned to his son, surprised. He was usually the first one to agree with every word Splinter pronounced, a habit his brothers teased him regularly about.

Raphael was as surprised as his father. He looked curiously at his brother. On Leonardo's other side, both Donatello and Michelangelo exchanged discreet excited glances. Would their brother dare to openly contradict their father? This was better than what they had expected.

Leonardo seemed to be caught in some kind of internal turmoil. Donatello tilted his head, intrigued. Was he trying to resist the serum?

"Leonardo, do you want to say something?" Splinter inquired, raising an eyebrow.

Leonardo finally blurted out.

"But Raph is right," he said while his blue eyes widened in horror, "the probability of either Donatello or Michelangelo winning the fight is so low that you don't need to take it into account."

His three brothers gasped. Master Splinter found himself speechless. This was extremely unexpected. Out of consideration for Leonardo's usual good behavior in the dojo, he decided to leave his son a chance to amend.

"Do you really think so?"

Leonardo closed his eyes, as if he couldn't bear to witness his father's reaction at what he was going to say. For an unknown reason, his tongue wasn't obeying him.

"Yes, I do. Donnie still leaves himself too open to a disarming attack and he doesn't take advantage of his long-range weapon. Mikey focuses more on having fun than on beating his opponent. Neither of them is a challenge right now. They do have potential, but they still have a long way to go."

"Hey!" Both affected brothers exclaimed indignantly while Raphael whistled, impressed in spite of himself by his brother's boldness.

"Leonardo! It is not your place to say so," Master Splinter said severely. He couldn't believe that Leonardo was being so disrespectful towards him and his brothers.

"I know, Sensei," Leonardo answered miserably. "I can't help it."

Splinter took a deep breath.

"You all have a long way to go before you truly master ninjitsu," he said. "Maybe you need to be reminded of that. Leonardo, stand up."

His son opened his eyes and obeyed, not daring to look at him.

"Fight me, without leaving yourself open for an attack. And don't forget to take advantage of your own long-range weapon."

Leonardo bit his lip. He had no doubt that he would be unsuccessful at both suggestions, and that it would hurt. With a deep sigh, he obeyed his father's command.

And it did hurt, when his body suddenly and violently came into contact with the hard wall while his katana scattered on the floor. He hadn't even seen his father coming. His brothers' laughs were ringing in his ears.

Ashamed, Leonardo sat down. What was happening to him? He knew better than to contradict his father. But it was as if he had had no choice but to speak his own mind.

Without paying attention to him, Splinter turned to his other sons.

"Change of plans. Donatello and Michelangelo, you spar with each other. The winner will fight Raphael. I don't think that Leonardo is in shape for another fight just now."

Donatello, Michelangelo and Raphael laughed again.

Donatello and Michelangelo faced each other and began circling. They were both smiling from ear to ear. This scene had been fun to watch and was a true balm for their hurt ego.

Raphael went to his fallen brother and extended his hand to him with a smile.

"Thanks for the support, but I'm surprised you didn't think this through," he whispered.

Leonardo groaned and took the offered hand to stand up.

"Sorry Raph, but I really didn't mean too. I don't know what has come into me," he whispered back.

Donatello and Michelangelo had finished their short-lived fight, the latter being the winner, and they had heard Leonardo's response.

"Don't worry, Leo, it happens to me all the time," Michelangelo told him comfortingly.

"Yes, it may be the biggest of your recent mistakes, but you'll get over it," Donatello added, twisting the knife a little.

"Oh no, it's not his biggest mistake," Raphael shook his head lightly before looking horrified.

Donatello immediately recognized this look. But Raphael hadn't been in contact with the serum recently, why would he feel compelled to tell the truth? Unless…

 _Oh no_ , Donatello thought. _Some of the serum must have mixed with Leo's sweat and didn't penetrate his skin. It stayed on his hand, and Raph touched it when he helped Leo to stand up. Now he's affected too._

A part of the purple-clad turtle was dying to hear what Raphael had to say, but another part of him wished he would shut up. Leonardo was looking at his red-clad brother with dread and something like betrayal in his eyes, and it made Donatello uneasy. Michelangelo seemed to be in a similar state of mind, because he didn't ask either.

Unluckily for Raphael and Leonardo, Master Splinter had no such scruples.

"What do you mean, Raphael?" He asked quietly, with a hint of warning in his voice.

Raphael looked at Leonardo, pleading. He didn't want to tell this, it was a secret between the two of them, but he really couldn't help it.

"I was referring to the time we met those sewage workers," he said. "When Leo decided to play Captain Ryan On A Solo Mission."

"Raph," Leonardo uttered.

Splinter blinked. He couldn't believe his ears. Was this a bad joke?

"Leonardo?" He asked his son very carefully.

"It's true," Leonardo said in a dead voice. His face was more white than green. If he had thought he was in trouble earlier, it was nothing compared to how he felt right now.

"When was it? Who was involved?" Splinter asked, his voice still incredulous.

"Four months ago. Just Raph and I," Leonardo answered automatically. "And it was my fault, not Raph's."

Donatello and Michelangelo were astonished. Had their brothers really been in contact with humans? Had they been hiding that from Splinter? If it was true – and it had to be, considering that both of them were under the influence of Donatello's serum – they were in big trouble right now.

"Our training session is over," Splinter said in a strained voice. "Donatello. Michelangelo. Leave us. I have to talk with your brothers."

The two turtles obeyed. As they exited the dojo and then the living room to take shelter in Donatello's lab, not even daring to spy on the coming conversation, Michelangelo turned to his purple-clad brother and grabbed one of his arms.

"Donnie," he whispered with a dismayed look on his face. "What have they done? What have _we_ done?"

"I don't know, Mikey," Donatello answered, putting his other arm around his brother's shoulder. "I don't know."

%%%%%

Splinter was pacing the dojo, trying to make sense of what had just happened and almost afraid to hear more.

Raphael and Leonardo were kneeling, their heads bowed, looking so guilty that their father had lost all hope of the whole matter being a mere joke.

Finally, Splinter stopped and took a deep breath, before kneeling in front of the two turtles. He closed his eyes for a second, finding his center and preparing himself to listen to his sons' story.

"Explain."

Leonardo and Raphael exchanged a glance without looking up at their father. Splinter sighed.

"Leonardo, you begin."

His blue-clad son found his voice. Although he was shaking slightly, his report was clear and surprisingly detailed.

"There had been this _Space Heroes_ episode where Captain Ryan was exploring this new planet on his own because his crew was ill, and I thought it was so cool and I would do the same on a sewer tunnel. So I waited until you were gone scavenging with Mikey. I knew Donnie would take advantage of Mikey's absence to work peacefully in his lab, and Raph would play his video games. I sneaked out of the lair and I chose a tunnel I didn't know…"

Splinter frowned. A tunnel Leonardo didn't know meant a tunnel in an area his sons were forbidden to explore. As if it wasn't bad enough that he had left the lair alone.

"… I began playing, but then I heard noises, and it was Raph. He had followed me."

Splinter turned to Raphael, who immediately took over.

"I had my suspicions because Leo was trying so hard to play the casual guy, so I was watching him. I spotted him leaving the lair, and I was curious and a little angry that he hadn't invited me or Donnie. When I understood what he was up to, I was mad at him and I shouted at him and he shouted at me and people heard us…"

Splinter's ears twitched. He turned to Leonardo. The blue-clad turtle went on without even blinking.

"They were sewage workers. We disappeared in the shadows like you taught us too, but one of them had ta-taken a glance at Raph…"

It was the first time that Leonardo stuttered in his story. His father forced himself to remain calm. His sons were in front of him, perfectly safe. They hadn't been captured, they hadn't been injured. The story ended well. This had happened months ago. All Splinter could do right now was listen to his sons. Leonardo was talking without catching his breath now and his father had to focus to understand him.

"… and he was saying to the others that he had seen a giant turtle and they didn't believe him but he wanted to show them that he was right and he was coming at us so I used a flashlight and I made a shadow show like Mikey had taught me while I was supposed to help him with his homework and when the sewer worker said that he had seen an elephant too they laughed at him but I think that's the giraffe who convinced them - including him - that he was hallucinating and they left and we went home and I'm so, so sorry."

Leonardo finally breathed. Splinter looked at him, speechless. When he found his voice again, it was to ask his other son a question.

"Anything else you want to say?"

"That I want to? No, absolutely not," Raphael whispered truthfully.

"So," Splinter went on. He was trying to order his thoughts. "Are you telling me that you almost got noticed by humans because you were shouting at each other in a sewer tunnel you were forbidden to explore, because Raphael had followed Leonardo who wanted to impersonate a cartoon character, and that you only got away because Leonardo had been playing with Michelangelo instead of helping him with his homework?"

Splinter's voice had risen with a remarkable regularity during his speech, and it was now terrifying for the two poor turtles in front of him.

"Yes," they both answered in a very small voice, their eyes set on the floor.

Splinter clenched his fists. He couldn't believe that his sons – and especially the usually so reasonable Leonardo - had been so careless. This cartoon had obviously a bad influence on him. What was he supposed to do now? Maybe he should borrow Donatello's laptop and go again on this Internet forum with helpful advice for single parents. And how could he, Splinter, have failed to notice that something this important had happened in his sons' life? He knew he wasn't a perfect parent, but it was still painful. Besides, he was retrospectively scared. The situation could have degenerated so easily.

Splinter looked severely at his sons. His effect was somehow ruined by the fact that they still weren't looking at him. He made sure that his anger and disappointment showed in his voice, and his sons shrank.

"Leonardo, Raphael, I am very disappointed in both of you. You disobeyed me and put yourselves at great risk."

Splinter took a cleansing breath.

"Leonardo, look at me."

His son obeyed. Splinter's heart sank at the tears welling up in his blue eyes, but he went on.

"Your behavior has been unspeakable. You know very well that I forbid you to leave the lair on your own and to explore certain tunnels for a very good reason. You're not safe in the world of humans. I thought I could trust you, and I was wrong."

"I'm sorry, Father," Leonardo choked.

"Besides, you didn't tell me anything about it until now…"

Splinter abruptly stopped. And why had they decided to tell him the truth today? They had managed to hide this from him for months, and they had seemed perfectly fine until then. True, Raphael's tongue had slipped, but he still could have found an excuse. Ninja master or not, Splinter would never have guessed on his own what had happened. Not to mention that it was highly unusual for Raphael to tattle on Leonardo. And why had Leonardo's report been so precise, with details he could have conveniently left out, like the part with Michelangelo's homework? It made no sense. Something didn't add up here.

The ninja master took a deep breath.

"I need to think about these events. We will speak later about your punishment. For now, you are both confined to your rooms. You may go."

The turtles didn't need to be told twice. They stood up and disappeared from the dojo, leaving their father with the beginning of a strong headache.


	5. Where More Than One Turtle Feels Guilty

_AN: Starfire201: Yes, it suddenly got a lot more serious. I guess it was only a matter of time until something went awry... Thanks for reviewing!_

 _BlingThing: I wonder too… Splinter IS suspicious now!_

 _Techno Dawn: Yes, he is! No doubt Leo rues the day he followed Captain Ryan's lead now._

 _Mikell: Poor turtles, right? It got so out of control. Thanks for reviewing!_

 _Nightshadegirl: Ahah, we will see what happens. But I don't think Donnie will dare to use his serum again any time soon, it would be too suspicious. Thanks for sharing your thoughts with me!_

 **Where More Than One Turtle Feels Guilty**

When Donatello and Michelangelo heard their brothers' footsteps in the living room, they tiptoed out of the lab to see how their talk with Splinter had gone.

However, they only glimpsed two green shadows hurrying towards the bedrooms.

Michelangelo bit his lip.

"I suppose it didn't go very well, then," he said, stating the obvious.

Donatello didn't answer. The purple-clad turtle had his eyes fixed on the corridor where his brothers had disappeared. He looked rather defeated.

"Do you think we should ask them?" Michelangelo asked.

"Let's wait a bit to be sure they are no longer under the serum's influence," Donatello answered slowly. "I think it has done enough damage for today."

Michelangelo sighed. Then he noticed his brother's expression and slid his arm around Donatello's shell.

"I wish we hadn't used your serum on Leo," he whispered. "It wasn't fun at all."

"I agree. If I had known…"

The purple-clad turtle shook his head, anger and hurt mixing with his guilt.

"But how was I supposed to know that they had been in contact with humans against Sensei's strictest orders? They told us nothing!"

"Do you think we should tell them about your serum?" Michelangelo innocently asked.

"What? No!"

In his surprise, Donatello took a few steps back, escaping Michelangelo's embrace. He faced his brother.

"Mikey, don't tell them about it. They don't need to know. It would only upset them more!"

"If you say so, Donnie." Michelangelo didn't seem convinced.

"I do. Listen, let's just… Let's just be there for them, okay? In case they'll need us."

Michelangelo nodded.

"Okay."

%%%%%

Leonardo was curled up on his bed, his blankets covering him from head to toe. Splinter's words echoed again and again in his head, hurting him a bit more each time. _I thought I could trust you, and I was wrong._

"I'm so, so sorry, Father," he whispered for the umpteenth time to his soaked pillow.

Leonardo tried to remember why he had thought that it would be such a good idea to explore this sewer tunnel on his own. It seemed so distant now. He had regretted his actions the moment he had heard those humans. From that moment on, he had only thought of getting Raphael out of danger. His brother had frozen and Leonardo had pulled him in the shadows, but it had been too late and someone had already spotted him. He knew they were lucky that his little trick with the flashlight had worked. For days after that, he had feared that the humans would send a search party though the sewers to find them. He had almost decided to go to his father and ask for his advice, but he had been too afraid and ashamed to do it. Raphael had been in a similar state of mind, and they had resolved to keep it a secret. As weeks passed and nothing happened, Leonardo had finally relaxed.

But now, his father knew.

Leonardo squeezed his pillow tighter. _I'll never be able to look him in the eye again_ , he thought dejectedly. At that moment, he was seriously considering never leaving his room again. He could stay here forever. He would ask Donatello to drill a hole in his door so that a food tray would pass. He would have all the time in the world to meditate on his shattering failure and…

"Pssst! Leo!"

It was Michelangelo's voice. Automatically, Leonardo straightened up and wiped his tears.

"Go away, Mikey," he whispered back, hoping that his voice wasn't too shaky. "I'm not supposed to talk to you."

"Did Sensei say so?"

"No, but he confined us to our rooms, so obviously we're not supposed to have visitors."

"It's not obvious to me," Michelangelo objected.

Before Leonardo could protest, his door opened to reveal an orange-clad shadow.

"Do you really need to stay in the dark? It's still morning."

Leonardo shrugged and discreetly tossed his soaked pillow away. He didn't want his brother to know that he had been crying.

"Are you okay?" Michelangelo inquired with a concerned tone. "You have been in there for an hour or so and we didn't hear anything."

"I'm fine," Leonardo lied outright. "Why don't you go see Raph?"

"He's beating his punching bag to a pulp right now. Don't you hear it? Donnie will go see him after he's done. We drew straws."

Leonardo listened. Now that Michelangelo spoke of it, he could indeed hear it. His heart sank as his thoughts turned to his red-clad brother. Raphael. Why had his brother betrayed him? But maybe he had had no choice. Like Leonardo himself, maybe he had been unable to prevent himself from speaking. It had been such a weird feeling.

Michelangelo hesitated.

"Leo, what happened? What did you do?"

"I don't want to talk about it," Leonardo muttered.

Michelangelo huffed and entered his brother's room, closing the door behind him. In the darkness, he crossed the room and climbed Leonardo's bed. Without a word, he curled up around his brother and squeezed him tightly.

Leonardo closed his eyes to focus on Michelangelo's hug. After a few minutes, he whispered the whole story in his ear. Michelangelo would eventually have learned about it anyway, and he could be an excellent listener when he needed to.

It was only after Leonardo had finished that the orange-clad turtle spoke.

"Wow. That's an amazing story. When I think that you almost met humans!"

Leonardo stiffened, concerned about the enthusiasm in his brother's voice.

"We were foolish. We could have been found out and captured and…"

Michelangelo squeezed him tighter. If Leonardo hadn't had a shell, he would have been unable to breathe by now.

"Relax, Leo. It didn't happen."

"But it could have."

"But it didn't."

Michelangelo hummed.

"You really used a shadow show to escape?"

For the first time, Leonardo smiled.

"Yes. Thanks for showing me how to do it, Mikey."

His brother giggled.

"An elephant and a giraffe. Not bad, Leo. But you could have done way better, bro. Like making the elephant and the giraffe dance together!"

Leonardo's eyes widened.

"Can you really do that?"

"Absolutely, brother mine! Do you want me to show you? Who knows, maybe it will come in handy next time you… hey!"

Michelangelo stroked his arm where Leonardo had poked him, sticking his tongue out at him. Too bad his brother couldn't see it in the dark.

"There won't be a next time," Leonardo told him firmly.

Michelangelo sighed.

"Such a shame. So… are you in?"

Leonardo hesitated. Then he switched on his bedside lamp.

"Go on, Shadow Theatre Master. You have my full attention."

%%%%%

Raphael sighed and threw himself on his hammock. His fists were aching. He had hit and hit his punching bag until his knuckles couldn't stand it.

He couldn't believe what had happened.

He couldn't believe that he had reported Leonardo to their father.

It had been exactly like last week. Suddenly, his tongue wasn't responding to his brain's desperate orders. He had hated every bit of it.

 _I'm sorry, Leo,_ he thought, forgetting that he was in trouble too. _I don't know what happened to me. I would never have betrayed you on my own free will. Never. Ever._

He heard a discreet knock on his door.

"Raph?"

Donatello's voice.

"Yes?" Raphael grunted.

"May I come in?"

Raphael thought about it. Of course, Donatello and Michelangelo would be worried about him and Leonardo. And of course they would be dying to hear the whole story. Was Michelangelo with Leonardo right now? It was a comforting thought. Raphael had wanted to stay at his blue-clad brother's side, but he hadn't dared to disobey his father. He knew that Leonardo was even more upset than him right now. Their father hadn't lectured any of them like that in years. But if Leonardo wasn't alone, then maybe Raphael didn't have to be either.

"Yes," he grunted.

Donatello entered his room with quiet footsteps and sat on a chair beside Raphael's hammock.

"Are you feeling better?" He asked hesitantly.

"Hmm. Maybe."

"Good."

The silence stretched.

"Don't you want to know what happened?"

"Of course I do. If you're ready to tell me."

Raphael was, and so he did. When he was finished, Donatello whistled.

"I remember that day. You and Leo avoided each other the whole evening, but when we watched a horror movie later, it was as if you were glued to one another. When I asked Leo, he told me that you had argued, but that it was settled now. I would never have thought…"

"Yeah, I know. I couldn't believe it either, really. I was so mad at Leo at first, and then so relieved that we had escaped and he was fine. That stubborn turtle and his stupid show."

Donatello shook his head.

"What did Sensei say?"

Raphael paused. He didn't know how much he could tell Donatello and how much was private.

"That he was disappointed in both of us. He… he was pretty harsh on Leo."

Raphael suddenly remembered something.

"But it was strange…"

Donatello tensed.

"What?"

"Sensei stopped in the middle of his lecture and dismissed us. He said he needed to think. I wonder why."

"Me too," Donatello whispered.

The room was silent.

"Hey, Donnie?"

"Yes?"

"Do… do you think that something is wrong with me?"

"Uh? Like what?"

"It's the second time I can't control my tongue. It was embarrassing enough the first time, but at least I was the only one concerned. This time…"

Raphael didn't end his sentence. After a while, he went on.

"I don't want it to happen again. Can you… can you look in your books and see if there is anything about it?"

"Of course, Raph. But you shouldn't worry, I'm sure you're fine."

"Thanks, Donnie. It means a lot to me. You see, I don't want to get my brothers into trouble because I can't control my big mouth."

"You're welcome, Raph. Do you need anything else?"

"Nah. Yeah. Spike's still in the living room. Can you fetch him for me? And bring me lettuce?"

"I'm on it."

"You're a true brother."

Donatello gulped. He had never felt so guilty in his entire life.

%%%%%

Splinter sat cross-legged in the dojo, breathing in and out deeply. He allowed his feelings to flow through his being. His anger. His disappointment. His fear. His concern.

His confusion.

He breathed, in and out, and little by little he felt his focus sharpen.

For now, he put aside Raphael and Leonardo's story and focused on their strange behavior. They had talked as if they had no other choice than to answer precisely every question. Precisely and truthfully, no matter the cost to them.

It reminded him of the events of last week, when Raphael had answered Splinter's questions in a way the ninja master was now sure his son had never intended.

That it had happened once could be a coincidence, but twice?

Was someone responsible for this?

Splinter took another deep breath. He had nothing to do with it. There were only four other possibilities.

Raphael and Leonardo were out of the picture for obvious reasons.

Michelangelo? His son loved to prank his brothers and made no mystery of it, but how could he have pulled such a prank? He had no means to do it.

Donatello? His most clever son, the one who could understand scientific fields Splinter had never heard of. The one who was always experimenting on something new, always trying to expand his knowledge. The one who was using his genius to help his family.

The one who would, out of curiosity, allow the object of his research to explode between his very hands.

Splinter would have to talk to him.


	6. Where Someone Investigates

_AN: Techno Dawn: I share your compassion. And it's true that Donnie needs it too… Thanks for reviewing!_

 _Nightshadegirl: Ahah! It would have been fun. But no, Splinter hasn't been in contact with the serum so far._

 **Where Someone Investigates**

Master Splinter was determined to get to the bottom of things. The sooner, the better. So he stood up, dusted his robes, took his favorite walking stick and went in search of his son Donatello.

He didn't have to go far. Donatello was in the living room, carefully holding Raphael's pet turtle Spike in his right hand and a big and barely stale lettuce in his left. Splinter watched him without making his presence known. His son was whispering to the small turtle.

"And now, to your master. He's a bit down, but you'll cheer him up, right?"

Splinter raised his eyebrows and followed him silently, watching him go into Raphael's room. The purple-clad turtle went out a few seconds later, closing the door quietly with a sigh. At the same time, Leonardo's door opened and Michelangelo tiptoed out of the room, looking unusually serious.

Splinter sighed. He couldn't say that he was surprised. His four sons were extremely close to each other, and of course Donatello and Michelangelo would do what they could to comfort their brothers.

He waited for Donatello and Michelangelo to come back into the living room, listening to their conversation.

Michelangelo was asking his brother.

"How was Raph? Did he talk to you?"

"Yes, he did. He wasn't at his best. I brought him Spike. And Leo?"

"Totally depressed, but I think I managed to cheer him up a bit. He told me the whole story. He's sleeping right now."

"It's half past eleven. In the morning."

"So what? He's emotionally exhausted, bro."

Splinter felt a pang of guilt, which he quickly dismissed. He was still mad at his sons for their foolishness.

Donatello was speaking again.

"Go figure Leo would do that. What was he thinking?"

"He just wanted to have fun. I can relate to that."

"Of course you can. Don't get any ideas."

Splinter's heart beat faster. Wild images of Michelangelo trapped in the midst of a crowd of sewer workers went through his mind. He cleared his throat.

"I hope you won't try to follow your brothers' poor example, Michelangelo."

Donatello and Michelangelo jumped.

"Sensei! I didn't see you, you are really stealthy today," Michelangelo articulated, giggling nervously. "Of course I won't, I was just kidding."

Master Splinter watched him with a stern expression and his son put on his best innocent face. His father sighed.

"I know it's not supposed to be your turn, but would you be so kind as to prepare our lunch, Michelangelo? I wish to speak with your brother."

"With me?" Donatello exclaimed with a slightly high-pitched voice.

It only increased Splinter's suspicions, as did the anxious look that Michelangelo not-so-discreetly gave to his brother. _Hmm. Is Michelangelo involved in this in some way?_ Splinter thought.

"Yes, with you, my son," he answered Donatello.

"I'm on it, Sensei," Michelangelo told him before he all but ran away to the kitchen.

Donatello stayed in front of his sensei, his fingers fidgeting nervously.

"What do you want to talk about, Sensei? Can I do something for you? If your bed is creaking again, I can fix it in no time and…"

"I just wanted to have your opinion on today's events, Donatello. I was wondering why your brothers would have wanted to confess to a four-month-old disobedience especially today."

Donatello inhaled abruptly.

"I don't know, Sensei. Maybe they were feeling guilty?"

Master Splinter watched him quietly. His son was obviously tense. He was more and more convinced that he had something to do with what had happened. Was he trying to lie to him? He should have known better. Splinter decided to play with him a little.

"Maybe, Donatello. Guilt can be a powerful motive. It can eat you from within until you become a shadow of your former self."

"I-it can?"

"Yes. It is not pleasant to see."

"I-I guess not."

"But it has nothing to do with you. Leonardo told me that you hadn't been involved. It is good to know that at least one of my sons didn't try to disobey me."

Splinter stepped up his game and put a hand on Donatello's shoulder. He felt his son shrink a little.

"I didn't even know that they were gone," Donatello told him in a small voice. "I was in my lab."

"Working on one of your experiments, is that right? Yours is a truly amazing mind, Donatello. By the way, what are you currently studying?"

"I-I'm in the middle of a chemical experiment."

"Really? That is highly interesting. Can you show me?"

Donatello's eyes widened.

"Now?"

As Splinter nodded, Donatello walked to his lab with the gait of a turtle convicted to death. He showed his father his collection of test tubes.

"Here. I'm investigating the properties of sewer waters when mixed up with other chemicals."

"And what did you find?"

"No-nothing special."

Splinter tilted his head. _Oh really? That isn't very convincing, my son._

The ninja master's attention was caught by a test tube slightly apart from the others. It was filled with a blue liquid and had been carefully sealed with a cork. From the corner of his eye, he saw Donatello turn pale. _That must be it._ Splinter took the test tube.

"What does this one do?"

"I-I don't know, I-I…"

Donatello fell silent. He wasn't used to lying to his father and he felt terribly uneasy. There was no chance that his father would fail to remark this or his uncontrolled stuttering.

"Donatello?"

Splinter bent toward the purple-clad turtle until his whiskers brushed past his son's skin. Somehow, he still managed to look wise and dignified.

"Are you sure there is nothing I should know about this?"

Donatello opened his mouth, closed it, blushed hard, absent-mindedly chewed his wrists' wrappings while thinking hard and finally gave in. Obviously, his father was suspicious and wouldn't give up. He would probably ask Michelangelo next, and the orange-clad turtle would tell him everything he knew. The best course of action for Donatello was to tell his father the truth himself. The genius watched the test tube filled with his serum. Such an irony. He was the only turtle of the four who hadn't been under the serum's influence, but in the end, he felt compelled to tell the truth just like them.

"It's a truth serum," he whispered. "I had no intention of making one, it just happened."

Splinter's eyes widened. He was impressed.

"You made a truth serum?"

Donatello nodded.

His father straightened up and inhaled deeply. Now the previous events made a lot more sense.

"Donatello, am I correct in assuming that you tested it on your brothers?"

Donatello hung his head in shame.

"Yes," he admitted.

Splinter furrowed his brow. Had his son been that careless?

"Without having any knowledge of the possible side effects?"

Donatello looked at him with intensity.

"It was harmless. Mikey tested it by accident – he surprised me while I was working and some of it dropped on him, and he was fine – and I performed additional tests."

Splinter watched him. This time, his son seemed sincere. Besides, he couldn't imagine that Donatello would willingly harm his brothers. Yes, Splinter would grant him that. He moved to his next question.

"Did you ask for your brothers' permission before using them as test subjects?"

Donatello's shoulders dropped.

"No," he said, ashamed.

"I see," Splinter whispered, his suspicions confirmed. Now it was easy for him to put the puzzle together. "I suppose that Leonardo and Raphael still have no idea of what happened to them, do they?"

Donatello shook his head, distressed. Splinter resisted the urge to tell him off. It would be much better – that is, far worse for Donatello – if he let his brothers deal with him.

"Then you will tell them after lunch. For now, give me everything related to this serum. Oh, and your computer, too."

%%%%%

When Michelangelo saw Master Splinter leave Donatello's lab with his arms laden with chemical equipment and Donatello's laptop, and his brother sadly go to his room, he knew it was only a matter of minutes before his father went to talk with him too.

The orange-clad turtle tried to focus on his saucepan, but he couldn't help starting at every suspicious noise or stealing glances at the kitchen entrance. He still didn't hear his father come inside.

"Michelangelo."

"Sensei?" The orange-clad turtle jumped.

"I've just had a very interesting talk with your brother. Did you know that he had made a truth serum?"

"Maybe?" Michelangelo tried.

His father tilted his head and the orange-clad turtle sighed.

"Okay, I knew. I tested it. But it was an accident!"

"And was it also an accident that Raphael and Leonardo tested it too?"

Michelangelo fell on his knees and joined his hands.

"Noooo, we pranked them! I'm so regretting it now! Please have mercy!"

Splinter sighed. This son of his had a pronounced taste for theatrics.

"Michelangelo, stand up. Do you realize how reckless you have been?"

Michelangelo sniffed convincingly and made puppy-dog eyes.

Splinter felt his heart melt. He nonetheless managed to watch him sternly.

"You will apologize to your brothers along with Donatello after lunch."

Michelangelo bit his lip. Somehow, he had known that this moment would come. He had a feeling that it wouldn't go well.

%%%%%

Michelangelo had burned his algae and worms soup, but nobody seemed to notice. Raphael was grumpily eating, Leonardo kept his eyes low and Donatello and Michelangelo exchanged apprehensive glances. Nobody was talking and lunch was over fast.

Splinter cleared his throat, immediately gaining his sons' attention.

"Donatello and Michelangelo, I believe that you have something to say to your brothers."

The two aforementioned turtles gulped while Leonardo and Raphael watched them with surprise.

"You begin," Michelangelo whispered to Donatello.

"Why me? It was your idea!"

"It was your invention!"

"What invention?" Raphael asked, frowning. "Donnie?"

The purple-clad turtle laughed nervously.

"Hey, Raph. You're going to find this so funny. I… I-kind-of-used-a-truth-serum-on-Leo's-katana-today-and-some-of-it-touched-you-by-mistake. I'm sorry."

Raphael's eyes widened and his mouth opened. Donatello couldn't even bring himself to look at Leonardo right now, so he didn't know what his blue-clad brother's reaction was.

"You what?" Raphael shouted. He couldn't believe his ears. "So it was your fault if I… if I… You traitor!"

The red-clad turtle turned to Michelangelo.

"And I suppose you helped him?"

Michelangelo nodded and hid behind Donatello.

"It was supposed to be a joke," he said in a very small voice. "We never meant to hurt you. I'm sorry too."

Raphael hit the table with his fists and the dishes clattered.

"A joke? I thought I was sick! And last week? Are you responsible for this too?"

"Raphael!" Splinter admonished him while Donatello and Michelangelo nodded timidly. "Calm yourself. I understand your anger, but your brothers can't be held responsible for your own actions."

Master Splinter quickly went on talking before Raphael could make a disrespectful remark. His hotheaded son was in enough trouble as it was. He glanced at Leonardo, who had said nothing. The blue-clad turtle was very pale and looked stunned.

"My sons. To various degrees, you all deserve to be punished for your actions. Here is what I have decided."

The ninja master had had a hard time trying to find appropriate punishments for them all.

"Leonardo and Raphael, you are the ones who had the worst behavior. You are both forbidden to leave the lair for the next month. You will also take on your brothers' cleaning duties for that period."

Splinter saw Raphael's incredulous look and he hoped that he wouldn't regret that decision. He made a mental note to increase his training so that his son wouldn't have any rebellious energy left.

"Leonardo, you are also forbidden to watch any cartoon until further notice. I will give you extra homework to keep you busy instead."

"Hai, Sensei," Leonardo whispered.

Splinter wasn't sure of that punishment either. He had read on the Internet that it was best to diminish little by little a person's exposure to the object of his addiction. However, he didn't know how this applied to cartoons. At first, he had thought of allowing Leonardo to watch one episode out of two, or maybe the first ten minutes of each episode. But he had decided that it didn't make sense.

"Donatello. From you, I expect an essay on the topic of scientific ethics. Let's say, two hundred pages long. You will then translate it in three other languages, including Japanese. I will also keep your computer for the next month. I will let you sort things out with your brothers on your own."

Splinter had an idea that it would be the most effective part of Donatello's punishment.

"Hai, Sensei," Donatello said sadly.

"Michelangelo, you will write an essay on the importance of thinking things through. You will use several examples related to the pranking field. I will expect fifty pages at least. I will also seize your comic books."

"But Sensei!" Michelangelo protested. "How am I supposed to avoid boredom without them?"

"You may watch educational channels. I have noticed that you have grown fond of them lately."

Michelangelo looked horrified.

"And now, I think I will rest in my room. We will have another training session this evening. In the meantime, I highly advise you not to disturb my peace and quiet."

After Splinter's departure, silence stretched in the kitchen.

"Uh," Michelangelo finally said for the sake of hearing his own voice. "Who is supposed to do the dishes, then?"

Leonardo stood up quietly and began to clear the table in silence. Raphael looked at him.

"You should let these traitors do it, Leo."

The red-clad turtle would have liked to punch his two other brothers right now, to teach them not to mess with his mind, but he had taken his father's warning very seriously. Donatello and Michelangelo winced at his harsh tone.

"Sensei said we were supposed to take on cleaning duties. I won't disobey him," Leonardo said flatly.

Raphael sighed. Of course he wouldn't.

"Fine. I'll help you, then."

Donatello and Michelangelo watched them with remorse. When they were done, Michelangelo tried to grasp Leonardo's arm, but his brother eluded him.

"Are you mad? Please don't be mad," Michelangelo said. "We never meant to hurt you, I swear!"

Donatello watched his brother's closed expression. He couldn't help but stating what was, in his opinion, the obvious.

"I'm sorry, Leo. But if you had trusted us and told us what you did, it would never have happened."

Raphael gasped. Obviously, he thought that his genius brother should have kept his logic to himself.

"You're right," Leonardo simply said. "I'll be in my room."

"Leo," Michelangelo moaned.

But the blue-clad turtle was already gone.

"I think that's a good idea," Raphael added in a menacing tone. "I don't want to stay in the same room as you two more than it is strictly necessary."

"Raph," Michelangelo whined.

Donatello rested his forehead on the spotless kitchen table. He had no doubt that he would easily write the essay that his father demanded from him. The translations shouldn't prove too hard either, even without his computer.

Sorting things out with his brothers promised to be far more difficult.


	7. Where Amends Are Made

_AN: BlingThing: Ahah! I know at least one turtle who wouldn't be afraid to ask. But none of the turtles would dare to use the serum on Splinter…_

 _Techno Dawn: Yes, Splinter wants to do his best as a father, but he doesn't feel especially competent as far as cartoons are concerned. And it's true that he has been softer on Donnie, but it doesn't mean that everything will be easy for that turtle…_

 _Nightshadegirl: Yes he will! Poor Mikey. At least it's still watching TV._

 _Starfire201: You're entirely right. Leo and Raph didn't intend to sideline their brothers, they were just too afraid and ashamed to tell them. Donnie really should have been quiet! Thanks for sharing your thoughts!_

 _Hawkfeather: Aww, don't worry about it. I appreciate that review all the more! And turtle hugs are indeed needed. Hmm… *whistles innocently*_

 **Where Amends Are Made**

When his sons entered the dojo for their evening training, Splinter could immediately tell that things weren't settled between them.

As they knelt in front of him, all four of them avoided his gaze. Michelangelo was stealing forlorn glances at Raphael and Leonardo. Raphael was frowning at nothing in particular and Leonardo's face was so expressionless that his father had no idea what he was thinking. Donatello's face was more readable. The purple-clad turtle looked sad and kept his head down.

Splinter inwardly sighed. After everything that had happened, he hadn't expected them to be light-hearted, but it still saddened him to see his sons unhappy.

As the training session unfolded, the atmosphere grew more and more awkward for the ninja master. Although his sons followed his every instruction, it was plain that their hearts weren't in it.

Raphael vented his frustration by punching and hitting harder than usual, and Splinter decided to pair him exclusively with Leonardo for this session, as a safety precaution.

Leonardo didn't look at his father for the entire session, and although he applied himself to perform the moves Splinter instructed his students to the best of his abilities, it was obvious that his mind was wandering miles away.

Donatello was apparently unable to focus and he tripped on his own bo staff once, something that hadn't happened in years. However, none of his brothers made fun of him or commented the fall, and he just picked himself up sadly.

Michelangelo was the most painful to watch. Splinter spotted him more than once trying to fool around when he thought that his father wasn't looking at him, in the hope of cheering his brothers up. Intentionally or not, they completely ignored him, and it made Splinter's heart ache to see his orange-clad son's defeated expression each time he failed to get their attention.

Finally, Splinter could have no more, and he cut the session short before sending his sons to bed. None of them complained.

When he retired to his own room a few hours later, Splinter hoped that tomorrow would be a better day.

%%%%%

Raphael couldn't sleep. He kept tossing in his hammock, finding no comfortable position. His mood was constantly switching between plain fury at Donatello and Michelangelo for intentionally tricking him into revealing his deepest feelings to everyone and accidentally leading him to tattle about Leonardo, and deep concern about the latter turtle, and it was driving him crazy.

He eventually gave up and stood up to check on his blue-clad brother. He tiptoed in the empty corridor between their rooms and stopped in front of his brother's door. He hesitated for a while. Should he try to open Leonardo's door? He didn't want to wake his brother up.

"What do you want?"

Leonardo's voice made Raphael jump, before he chided himself. He shouldn't be surprised that Leonardo would be awake too, nor that he would have sensed his presence.

"Nothing, he grumpily answered, keeping his voice low. "I was just passing by. On my way to the bathroom."

"The bathroom is in the opposite direction."

"Is it? I must have been confused, then. It's dark."

Raphael heard a sigh, the sound of blankets being shuffled, and a few seconds later the door opened. Leonardo sounded exhausted, but there was the slightest hint of amusement in his voice when he answered his brother.

"Since when does the dark bother you?"

"It doesn't bother me. It confuses me. But as I'm here, and you're here, and neither of us is sleeping, why don't we have a little chat?"

"About what?"

"About the fact that you didn't tell anyone anything about what Donnie and Mikey did. Or didn't talk to anyone for the whole evening, for that matter."

"I've got nothing to say about it."

"Liar."

Leonardo rolled his eyes.

"I've got nothing positive to say about it."

"That's better, but still not enough."

Leonardo muttered something indistinct along the lines of "Stubborn hothead." Raphael smiled and took it as his cue to enter.

Leonardo laid down on his bed, leaving room for his brother. Raphael made himself comfortable before speaking again.

"I'll begin. I'm mad at them both. Right now, I want to punch them until they beg for my mercy in at least twenty different creative ways, including an ode to my greatness."

Raphael heard Leonardo stifle a laugh and inwardly congratulated himself.

"I'm pretty sure it's a very bad idea. Though I might enjoy watching it."

"You'll be welcome. And now that I've told you about my evil plans of revenge, it's your turn."

"I have no evil plans of revenge."

"What a shame. At least, tell me how you feel about their little prank."

Raphael felt Leonardo stiffen. He knew how hard it was for his brother to share negative feelings. Raphael could relate to that, sharing any kind of feeling was hard for him. However, he had no intention of letting Leonardo deal with that mess alone. He waited patiently, moving in an indifferent way so that his hand accidently landed on his brother's shoulder.

"Okay," Leonardo whispered reluctantly. "I feel betrayed. I would never have expected that from Donnie and Mikey."

"You and me both."

"It… it really hurts. To know that they didn't care about what I would feel."

"Same here."

Both brothers sighed. After a while, Raphael punched Leonardo's arm lightly.

"See? It wasn't that difficult."

"You're one to talk," Leonardo said wryly. "But… thanks, anyways."

"Don't mention it."

A comfortable silence stretched. Raphael was about to fall asleep when he heard a knock on the door.

"Yes?" Leonardo whispered.

The door opened. It was pitch black, but neither Leonardo nor Raphael needed to see to recognize the turtle standing awkwardly there. He was betrayed by his light footsteps and the way the door frame cracked when he leaned against it.

"What do you want, Mikey?" Leonardo asked in a neutral tone.

"I… I had a nightmare."

Michelangelo's voice was a mere whisper.

"Why don't you go to your favorite partner-in-crime, then?" Raphael grumbled.

Michelangelo jumped.

"Raph? You're here too?"

Then the meaning of Raphael's sentence hit him and he uttered his next words in a trembling voice.

"I'm sorry, guys. I'm so, so sorry. Please forgive me. I don't want to lose you!"

The mattress lifted, Raphael's only clue that Leonardo had got up.

The next second, Michelangelo was bursting into tears, muttering continuous apologies. From the way his voice was muffled, he must be buried in someone's embrace.

"Shh, Mikey," Leonardo whispered. "You won't lose us."

Raphael sighed. It wasn't fair if Michelangelo was crying. How was he supposed to stay mad at him?

He got up and embraced his two brothers.

"Of course you won't, Mikey," he grumbled. "You idiot."

"I-I dreamed that you would never forgive me nor speak with me nor look at me again," Michelangelo told them, sobbing. "A-and I knew that I had deserved it, but it s-still hurt so much."

Leonardo moved to his bed, pulling his brothers along. He leaned on his pillow, Michelangelo huddled against him with Raphael on the other side of the orange-clad turtle.

"Oh, Mikey," Leonardo told him gently. "We would never do that to you."

"Then you're not mad at me?" Michelangelo sniffed hopefully.

"Not anymore," Leonardo sighed. "Though I'll admit that I have been."

Raphael said nothing, but he squeezed his brother hard.

"I'm sorry I hurt you," Michelangelo whispered again. "It was supposed to be a fun little prank."

"What were you thinking, Mikey?" Raphael reprimanded him. "It's not fun to feel robbed of one's freedom to speak."

"You know I never think things through."

"You're saying it like it's something to be proud of," Leonardo remarked.

"It usually is," Michelangelo answered sleepily. "Can I stay with you tonight?"

"Of course. But please avoid pushing me out of my own bed."

Michelangelo let out a small laugh.

"I'll try."

"Do better than that," Raphael threatened him playfully. "Or I will punch you."

"Yay, Raph is staying too," Michelangelo yawned.

Raphael smiled and curled up around the already sleeping turtle while Leonardo pulled his blankets so that the three of them were neatly covered. The red-clad turtle was rejoicing in his brothers' presence and carefully avoided thinking about the fact that one of them was missing.

%%%%%

Donatello was having a difficult time. He didn't know how to tell his brothers how sorry he was for what he had done, and he was almost jealous of Michelangelo, who had somehow managed to make his peace with them during the night.

They didn't make it easy for him either. Raphael was sending him furious glances each time he had to do Donatello's chores, and Leonardo was more withdrawn than usual, disappearing for hours in his room to do his extra homework. Donatello wanted to offer him his help, but he was afraid of being rejected.

So he focused on his essay and its translations, which ended up much longer than necessary. When he handed Splinter the two thousand pages, handwritten because Splinter had confiscated his computer, his father thanked him with a face that Donatello didn't quite know how to interpret. It was almost as if the giant rat suddenly regretted having given him that punishment.

Then the purple-clad turtle busied himself with every repair that their lair needed, and quite a few that weren't needed at all. He tried to make his brothers' life easier by inventing more efficient cleaning products, but chemistry had lost its appeal to him.

Training sessions were painful too. Raphael was going as hard on him as he could without awakening their father's wrath, and Leonardo was fighting almost mechanically, which was painful to witness. At least Michelangelo managed to get a smile out of the blue-clad turtle from time to time.

Even watching educational channels with Michelangelo wasn't as fun as it had been. Donatello thought about the situation, and the more he thought about it, the less he knew how to get back to normal. He wanted Raphael to tease him about his so-called useless research before pleading with him to fix his headphones, and to smile at him when he was winning their fights. He wanted Leonardo to ask him questions about his latest invention and to help him in the dojo. He wanted to sit with his three brothers to watch Leonardo's favorite cartoon, to see the blue-clad turtle so engrossed in his show that he would unconsciously imitate Captain Ryan's moves from the couch, to hear Raphael tease their brother about it and to feel Michelangelo's weight on his shell when the suspense would become overwhelming.

One evening, he confided in Michelangelo.

"I don't know what to do, Mikey. I don't know what to tell Leo and Raph so that they won't be so mad at me."

"Why don't you just tell them how you feel? That's what I did."

"I don't think they will believe me. They don't trust me anymore, and I can't blame them."

"You're worrying too much. Why would they think that you're lying?"

"Because you can never know if somebody is telling the truth or not…Except…"

"Uh?"

"Never mind. Thanks, Mikey."

Donatello rushed to his father's room and cleared his throat before knocking. The painted screen slid and his father appeared.

"Yes, Donatello?"

"Father," Donatello asked with a pleading voice. "I need your help."

%%%%%

Leonardo and Raphael were in the middle of mopping the floor of the living room when Donatello burst out from the dojo and stood in front of them, a strange expression on his face.

"I'm sorry."

His brothers exchanged a glance.

"You already told us so," Leonardo said quietly.

Donatello took a deep breath before going on.

"I was so curious and so proud of my truth serum that I didn't think about the consequences, and especially about how you would feel. I've been stupid and careless and insensitive."

Raphael blinked.

"That's… true."

"I've been trying to tell you how sorry I am, but I couldn't find the right words. I want you to know that I deeply regret what I have done, and that I love you so much and that it hurts that you're sidelining me, and that I tried to help you with your chores but I couldn't invent anything but I really wanted to, because I know how hard it can be to scrub the shower after one of us has been scavenging and…"

"Donnie, are you alright?" Leonardo finally interrupted him. "You're rambling."

"No, I'm hurt and sad and guilty and..."

"Dude, did you take some of your own serum?"

The three turtles turned around to see Michelangelo, wide-eyed.

"Did you?" Leonardo asked with concern while Raphael gasped.

"I did. It was the only way I could be sure that you would believe me and I really, really need you to believe me. And now, you can ask me a-anything, and I will have no choice but to answer."

"Donnie…"

"I know we won't be even, but I hope that it will help a bit and…"

"Donnie!"

Leonardo reached for his purple-clad brother and grabbed his shoulders, letting his mop flop to the floor.

"I want you to shut up and listen."

Donatello closed his mouth and looked at his brother with a pitiful expression. Leonardo's eyes were shining with conviction.

"It's true that I have been mad at you, but now I just want to have you back and I was wondering why you hadn't come to us yet. You're our brother, and brothers forgive each other."

Leonardo hugged Donatello, who sniffled against his shoulder, his head bowed because of the height difference.

"I'm not going to use the occasion to learn anything that you don't willingly want to share with me," the blue-clad turtle firmly said, stroking Donatello's neck soothingly.

"That's very magnanimous of you, Leo," Raphael said. "But I think I will."

Donatello watched him with sad eyes, and Raphael sighed before patting his shell.

"What Leo just said for the brotherly part, though."

Leonardo rolled his eyes.

"Aww, how cute!" Michelangelo exclaimed before launching himself on Raphael, who grasped the first thing within his range to keep his balance, aka his brother Donatello. The four turtles landed on the floor, Michelangelo laughing happily on top of them. Raphael groaned. Why did he have to land on Leonardo's discarded mop?

"And I think I will use this occasion too, brother mine," Michelangelo exclaimed. "It's only fair that I learn about your secrets too."

Donatello smiled. He would pay any price to have his family around him again.

"Why? Did he use his serum to blackmail you?" Leonardo's eyes widened. "That would explain your sudden taste for scientific shows!"

"Then we will learn about Mikey's secrets too," Raphael said with satisfaction from his place at the bottom of the turtle pile. He smiled evilly at Michelangelo's horrified expression. "This is going to be a good day after all."


	8. Where Someone Learned His Lesson

_AN: Techno Dawn: Thank you so much for the compliment! I really see Raph that way. And Donnie needed to set things right with his brothers._

 _Hawkfeather: You're welcome! This is the last chapter. I hope you enjoy it! And thanks for reviewing in such detailed fashion. :D_

 _Nightshadegirl: More exactly, it's Donnie who does, but Donnie knows Mikey's secrets… Will he be able to keep them to himself?_

 **Where Someone Learned His Lesson… Maybe**

"I can't believe it! I can't believe it!" Raphael kept repeating, Michelangelo's head in an armlock. "My punching bag! My weights! My towel! My blankets! And…" He used his other arm to smack his orange-clad brother on top of his bowed head. "Spike's bowl! Is nothing sacred to you?"

"Ow!" Michelangelo exclaimed. "Donnie, why?"

"I can't help it, Mikey," Donatello answered sheepishly. "I have to tell the truth, remember?"

"That's quite an impressive list, Mikey," Leonardo commented. "Do I even want to know what you did to me?"

"Noooo, you don't!" Michelangelo exclaimed. "Leooooo, have mercy!"

"I do," Raphael replied far too happily. "Donnie, what pranks did Mikey pull on Leo? Only the ones that we don't already know about, of course."

"Well, there is that time when he messed up the clock of our video recorder, so Leo would record the local news instead of the next episode of _Space Heroes_ …"

"It was you?" Leonardo's eyes gleamed dangerously. "I had to wait two entire days before they rebroadcasted it on another channel!"

"A mere mistake!" Michelangelo protested.

"And that time when he added old hand cream to Leo's choji oil…"

Raphael burst into laughter.

"So that's what happened! This was a good one, Mikey. Leo's face was priceless!"

"Didn't you like it? Your katana gleamed so beautifully!" Michelangelo tried, without much hope.

"I thought the oil had become stale! I threw out the entire pot!"

Leonardo clenched his fists. He asked Raphael in a very calm and polite voice.

"Raph, if you would be so kind…"

"But of course, Leo!" Raphael was still laughing. "He's all yours!"

The red-clad turtle released Michelangelo, who yelped and tried to escape. But Leonardo was ready and he tripped him before pinning him to the floor.

"My katana are off-limits, Mikey," the blue-clad turtle threatened, enunciating every word. "Don't you dare do that again, or I will test their edge on your precious comic books next time."

"No no no no! I won't do it again, I promise!" Michelangelo pleaded. He had no doubt that Leonardo would follow through with his threat.

Donatello chuckled. Michelangelo's secrets were more dangerous to him than his own had been to the purple-clad turtle. It helped that Donatello rarely pranked his brothers, although Raphael hadn't been too happy to learn that the genius and self-appointed repairer of the family coincidentally lacked the necessary equipment for Raphael's urgent repairs when the red-clad turtle had especially annoyed him during training.

Fortunately, Raphael's wrath had been soothed by Donatello's admission that he had secretly regulated their hot water tank so that the red-clad turtle could take a shower a tad colder than the others, just like he liked it. The regulation mechanism was triggered by Raphael's regular kick in the wall when he entered the shower, which had embarrassed the hothead. He hadn't known that Donatello was aware of this particular habit.

Donatello had also owned up to his unhealthy sleeping habits, and learned at the same time that it was hardly a secret.

All in all, he was getting by fine, although he hated the fact that he was compelled to talk. It shamed him all the more to know that he had forced his brothers to experience that feeling.

He looked at Leonardo, who was now mercilessly tickling Michelangelo with Raphael's helpful support, and he chuckled again. Unluckily for him, it caught Raphael's attention. The red-clad turtle grinned threateningly at him, and before Donatello had time to register what was happening, he was pinned to the floor next to Michelangelo, laughing hard.

The situation degenerated quickly into a tickling match, who was abruptly interrupted when Master Splinter cleared his throat. The four turtles on the floor watched their father sheepishly.

The ninja master raised an eyebrow and shook his head.

"There will be no training this evening," he finally said. "I believe that you already got enough exercise."

"Thanks, Master Splinter!" Michelangelo expressed with gratitude.

The orange-clad turtle took the occasion to catch his breath. As soon as Splinter's figure disappeared, he would get back at his brothers with all the might of his tickling fury.

%%%%%

Splinter rejoiced in the fact that Donatello had finally made up with his brothers. His sons were now closer than ever. However, one of them was still worrying him.

At the beginning, he hadn't been surprised that Leonardo avoided meeting his gaze or didn't talk to him if not spoken to. It was obvious that his son was ashamed of what he had done, and Splinter thought that it was only appropriate.

However, as days, then weeks passed and Leonardo still avoided him, spent his whole free time either cleaning or doing homework and didn't seem to enjoy training sessions as much as he used to, the rat father began to suspect that maybe he was hurt deeper than Splinter had intended.

The ninja master had hoped that making up with Donatello would help him find his balance again, but he had been disappointed. One afternoon, as Splinter was drinking his cup of tea alone – Leonardo hadn't joined him since he had owned up to his disobedience – he decided that he had had enough. It was time to take matters in hand.

Splinter sighed with wistfulness. When his sons were younger, they always rushed to him whenever they felt sad or in pain. He had secretly enjoyed tending to their grazes and soothing their children's sorrows. It had been easier then. _Or more likely, I have conveniently forgotten all the times I've felt at a loss,_ he thought wryly.

Splinter stood up and left the dojo in search for Leonardo. In the living room, Donatello, Michelangelo and Raphael were watching a movie about the life of insects.

"Where is your brother?" Splinter inquired.

Donatello, engrossed in the show, didn't register his presence. Michelangelo looked at him unhappily and Raphael answered hesitantly.

"He's in his room."

"I see. Thank you."

Splinter went to Leonardo's bedroom and knocked on the door.

"Thanks Donnie, but I have to do it on my own," Leonardo's reply came from the other side of his door.

"I am not Donatello," Splinter answered softly.

He heard the sound of a chair scraping the floor and the door opened.

"I'm sorry, Sensei," Leonardo said sheepishly, his eyes set on the wall behind Splinter's back. "What can I do for you?"

Splinter sighed inwardly.

"I wish to talk to you. May I come in?"

"Of course," Leonardo answered uneasily.

Splinter entered Leonardo's room and sat on the perfectly made bed. He patted the blankets next to him and his son hesitantly sat down.

"Leonardo. Why aren't you watching TV with your brothers? I didn't ban you from watching every show."

"I have homework to do."

Splinter glanced at the pile of books on Leonardo's desk.

"It is not due until the day after tomorrow."

Leonardo didn't answer. He was busy twisting his wrist wrappings.

Splinter tried another approach.

"And why don't you share tea with me anymore? I miss you."

His son glanced at him with surprise.

"I… I didn't think you would want it."

"Why not?"

Leonardo swallowed hard.

"Because I cannot be trusted. Why would you want to spend time with a son like me?"

Splinter inhaled sharply. Was it how his son really felt?

"Because I love you. You know how much I do, right?"

"I don't deserve it."

Leonardo's answer had been a mere whisper. Splinter felt his heart break. He pulled his son into a tight hug and fought to find the right words.

"That's not the point. You don't have to deserve my love, Leonardo. Besides, it isn't true. Your worth isn't erased because you make mistakes, my son."

Splinter waited while Leonardo was sobbing in his arms, stroking his son's head gently and not caring an iota if his robes were getting soaked. When the blue-clad turtle had calmed down, his father asked him softly.

"Is this also the reason why you have been so withdrawn during our training sessions?"

Leonardo nodded pitifully against his father's chest.

"I didn't think I deserved to enjoy them after what I did."

Splinter shook his head, amazed. He placed a finger under Leonardo's chin and lifted it so that his son would look at him, and talked to him severely.

"Leonardo. I already punished you. You don't punish yourself on top of that. Understood?"

"Yes, Father," Leonardo answered sheepishly.

He used his bandana to wipe his remaining tears before burying his head in his father's robes once more.

"I swear, I would never have done it again, even if you had never known," Leonardo whispered.

Splinter squeezed him softly.

"I believe you, my son."

Later that day, Splinter was watching the test tube containing Donatello's truth serum. It had really made a mess of their lives. Truth could be dangerous.

Splinter hummed. An idea suddenly occurred to him. It would require some training to make sure that it was possible, but the ninja master was fairly confident that it would work.

Maybe he could teach his sons a final lesson before they all moved on.

%%%%%

At the end of the month, the four turtles and their father gathered in the dojo.

"My sons. I am happy to say that your punishments are now over. And yes, Michelangelo, this means that you and Donatello will take your cleaning duties back."

"Such a shame," Michelangelo muttered, causing Raphael to glare at him.

Splinter went on with his lecture.

"You all tried to fix your mistakes to the best of your abilities, and for that, I am proud of you. I hope that you all learned a valuable lesson."

Leonardo nodded, his eyes fixed on him. He had finally forgiven himself, to his father's utter relief.

Raphael rolled his eyes. He was eager to leave the lair again. He loved to scavenge with his father and to play in the sewers tunnels near the lair with his brothers. Couldn't Splinter just be done with his lecture?

Michelangelo was hardly focusing on Splinter's words. He was thinking of his next prank. It wouldn't involve Leonardo's katana or Spike's bowl, that was for sure.

Donatello watched his father with attention. Was he dreaming or were Splinter's eyes twinkling?

"While truth is a foundation of trust, the truth is sometimes better left unsaid," Splinter was going on. "And you should learn that truth should be treated cautiously."

"What do you mean, Sensei?" Leonardo asked.

Splinter opened his hand to reveal the truth serum.

"I will show you."

Under his sons' amazed gazes, he tilted the test tube until one drop of it landed on his palm.

"Sensei, what are you doing?" Donatello exclaimed.

"I'm dropping some of your serum on my palm."

"That's not exactly what I meant."

"It's still the truth. Now I will allow each of you to ask me a single question. Choose wisely."

Michelangelo bounced.

"I know, I know! Who is your favorite son?"

"Mikey!" His brothers exclaimed.

Splinter hid his smile. He had anticipated that question, and his entirely truthful answer was ready. He had even rehearsed it in front of a mirror.

"Michelangelo is my favorite son…"

"Ah! Do you hear that? I'm Sensei's favorite!"

"… for folding origami. Donatello is my favorite son for playing Go. Raphael is my favorite son for watching wrestling competitions. Leonardo is my favorite son for drinking tea."

His four sons looked at him with incredulity.

"It's not an answer!" Michelangelo protested. "You chose activities that the others don't like anyway!"

"It is my answer, and it is true. Now, who wants to ask something?"

Donatello tilted his head.

"Did you read my essay?"

"I read every interesting part of your essay, my son," Splinter answered. _That is, the introduction and the conclusion._ But he didn't add that part. He could resist the urge to say the whole truth as long as he still said the truth – he had checked it.

Donatello pouted. It wasn't the answer that he had expected.

Raphael was next.

"When are you going to allow us to go to the surface?"

Splinter stifled a chuckle. Another predictable question.

"When I will judge you to be ready. Leonardo, it is your turn."

"How are you managing to select the part of the truth that you want to tell us?"

"I'm using my spiritual training. And I practiced."

His four sons were looking at him in awe, which Splinter quite enjoyed.

"Truth isn't always straightforward. On the contrary, it can be ambiguous or even multiple. I hope you learned that today."

"We certainly did," Donatello mused.

"Now, Donatello, I will ask you to get rid of this serum. It is not to be used again in this lair. Do we agree on that?"

"Hai, Sensei," the four turtles answered.

"I will dispose of it immediately," Donatello said, extending his hand to take the test tube from his father's hand. Of course, he would still remember the formula. But he didn't think that he would use it ever again. At least, it was highly unlikely.

"Then you may go."

"It's a pity we could only ask one question," Michelangelo sighed while leaving the dojo. "I had many other ideas! Like, how come he doesn't use more soap when he takes a shower? With all his hair."

"Mikey!" Leonardo exclaimed.

Splinter was still within earshot. He smiled.

"That's because I regularly lick it to keep it clean," he said with solemnity.

His sons exclaimed in disgust.

"I really didn't want to know that," Leonardo complained, running for his life with his brothers on his heels for fear of learning other embarrassing details about their father's routine.

Alone in the dojo, Splinter laughed.

%%%%%

 **Epilogue**

Years later, Leonardo is kneeling next to Donatello with guilt written all over his face.

The purple-clad turtle is still lying on the dojo floor, his pain slowly receding. Raphael and Michelangelo are at his side too, with April and Master Splinter not far behind.

Karai has just departed, her words of revenge still hanging in the air. Leonardo is concerned about her, but it can wait. Right now, he needs to apologize to his brother, who has just woken up.

"Donnie, I'm so sorry. I should have told you guys what I was up to."

What he was up to, namely go after Shredder's possessions with Karai behind Splinter's back. That disastrous scheme resulted in Donatello being hurt in a chemicals factory explosion while he was searching for Leonardo with Raphael and Michelangelo.

Donatello looks at him with exasperation and love.

"Yes, you should have," he says.

Then he pulls his temporarily black-clad brother into a hug, wincing because he's still hurting from the impact.

"I forgive you. You're our brother, and brothers forgive each other," he whispers in Leonardo's ear, knowing that he will remember.

Leonardo does, and he smiles at the words he offered Donatello all those years ago.

 **The End**

%%%%%

 _Author's Note: And the story is over! It was fun to write, even if it was longer than I usually intended. *stifles the small voice who is trying to tell that it was supposed to be a quick one shot*_

 _The epilogue was inspired by the Broken Foot episode of the 2012 cartoon._

 _Thanks again to every person who showed an interest in this story! Without your reviews, favs and follows, I would never have been able to write half as fast as I did. You are wonderful._


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